


Not a Sword

by secooper87



Series: Adventures of a Line Hopper [12]
Category: Buffy the Vampire Slayer, Doctor Who
Genre: Action/Adventure, Angst and Humor, Crossover, Dark Comedy, Humor, Timey-Wimey
Language: English
Status: Completed
Published: 2012-03-16
Updated: 2012-03-22
Packaged: 2017-11-02 01:15:32
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 9
Words: 15,236
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/363394
Author URL: https://archiveofourown.org/users/secooper87/pseuds/secooper87
Summary: <blockquote class="userstuff">
              <p>The Doctor and Donna are looking for a mythical English sword. That doesn't look like a sword and doesn't act like a sword. In California. In 2000 AD. With a toaster. Let the "Oi's" begin!</p><p>(Yes, it's rated Teen, but it's a seriously tame Teen.  If you're old enough to watch Buffy, you're old enough to read this.)</p>
            </blockquote>





	1. Chapter 1

"So you're saying we're looking for a sword," said Donna.

The Doctor was flitting around the TARDIS, removing panels of grating and pulling out different items that looked (to Donna) like things you'd find in a rubbish sale back on 21st century Earth. He'd then examine every item using his 'brainy specs', rotate it in his hand, then chuck it aside.

"Possibly," said the Doctor, darting to another panel of metal grating. "But possibly not. It could be anything, Donna! Anything!" He pulled out an item that very much resembled the engine car of a model train set. "A grain of sand, someone's left shoe, maybe even a snowflake — but not a snowflake." He chucked the model train over his shoulder, and then continued searching. "Southern California. Very little snow. Almost certainly not a snowflake."

"So we're not looking for a sword," Donna clarified.

"Might be a sword," said the Doctor. "Might be anything. Um, not a scythe, though — that's hidden round about the same place. Know about that one. But yes. Possibly a sword. Like I said before, could be anything."

Donna wondered, sometimes, how exactly it was the Doctor's brain worked. "Doctor, you said we were looking for Excalibur."

"Ah, yes, well, not really Excalibur, just the nearest equivalent thereof," said the Doctor. "In this universe, at any rate. Last Excalibur I found was from the Arthurian Universe. Nearly wound up destroying modern England with a nuclear warhead, that did."

Donna had little or no idea what that could possibly mean, so she decided to ignore it.

"And we're looking for Excalibur," continued Donna, "which is a mythical sword once wielded by the King of England, in California. In the year 2000. AD."

"Exactly," said the Doctor. He finally lifted out a device that looked a little like a toaster, if said toaster had been designed by both Albert Einstein and Frank Lloyd Wright. The Doctor grinned at it, and put the grating back. "There you are! Good as new. What did I tell you?"

Donna crossed her arms. "Doctor," she warned him.

"Oh, yes, sorry," said the Doctor, standing up to face her. Then he hesitated, as he realized he wasn't quite sure why she was mad at him. "I, er…" he raised up the device. "Psychic augmentation detector?"

"I want to know," said Donna, in her best don't-mess-with-me voice, "exactly what it is we're looking for, why we're looking for it, and why we're looking in bloody California!"

The Doctor hesitated. "We're looking for a segment," he admitted. "A segment to a very powerful Key. It could be disguised as anything, anything at all — but it has the power to crack open the walls between dimensions. Just like Excalibur! See?"

"No," said Donna.

"Well, Excalibur wasn't actually a sword, it was a key to a trans-temporal, trans-dimensional, trans-universal gateway which could—"

"Doctor," Donna cut in, before the techno babble could start up again in full. He looked at her, a single eyebrow raised. Donna cleared her throat. "We are looking for a mythical English sword. In California. A sword that doesn't look like a sword. And doesn't act like a sword."

The Doctor shrugged. "Suppose so."

"So if it doesn't look like a sword and doesn't act like a sword, then what about it makes it a bloody sword in the first place?" Donna demanded.

"Ah," said the Doctor. "It's… actually… not a sword. At all. Just a segment."

Donna decided that this was Spaceman talk for 'stop asking me stupid questions, Donna, and play along.' Fine. She'd do that, then. "Okay," said Donna. "So, assuming we can actually find this 'sword that isn't really a sword', what are we going to do with it?"

"Destroy it," said the Doctor. "Best thing, really. You don't want to go messing with trans-temporal, trans-dimensional, trans-universal portals, Donna, take my word on it. Daleks, Cybermen, nuclear bombs — never know what'll turn up, really. And if that segment ever leaves this solar system, if it destabilizes the Lock — well, best not even think about that."

"And you've got the toaster because…?"

The Doctor raised up the super-toaster. "Not a toaster," said the Doctor. "Psychic augmentation detector. Whoever's hidden this thing really didn't want it to be found. Memory alteration, psychic manipulation, the works. Even a fair amount of matter transmutation, actually. Not to worry, though. This'll pinpoint the locus of the psychic interference matrix."

"In English?"

"We're looking for something that has suddenly popped into existence," explained the Doctor. "Except no one in the town knows that it's popped into existence, because someone's cast a magic spell to make everyone believe this object has always been there."

Donna thought she actually understood that. She must be learning to speak Spaceman. "So all we have to do is jog these people's memories so they'll realize the sword isn't actually supposed to be there in the first place. Then they'll give us the sword, and we can destroy it."

"That's the plan," said the Doctor. "And, well, if they still don't feel like giving it to us, we'll just nick it."

"We're going to wind up running for our lives again, aren't we?" asked Donna.

The Doctor grinned. "Oh, yes!"

Donna looked down at what she was wearing — a tasteful skirt with beautiful black high-heel shoes. "All right," she said. "Let me get changed."

**Notes for the Chapter:**

> I have been debating whether to post this before or after "Elizabeth", because the two stories sort of need pieces of each other. I've decided to post this first, but with a little excerpt from "Elizabeth". So, here's a preview of "Elizabeth" (taken from the Coda):
> 
> _"I… have a new boyfriend, now," Buffy said, mainly because she didn't know what else to say._
> 
> _The Doctor didn't answer her._
> 
> _Buffy tucked her hands into her jeans pockets. "Yep," she said. "He's… Riley. That's his name. His name's Riley."_  
> 
> _"Ah. Riley."_  
>     
>  _Buffy looked over at the Doctor. "You've met him?"_  
>     
>  _"Day I met him," said the Doctor, "he tried to kill me."_  
>     
>  _Buffy's eyes grew wide. "Wait, what?"_  
>     
>  _The Doctor glanced over at her. "Don't worry," he said. "He'll have a good reason." He frowned. "An extremely good reason. You'll think so, too, when it happens."_


	2. Chapter 2

The Doctor was angry with his toaster. Probably because it wasn't working right. Or because he simply didn't like it anymore. Or maybe he just didn't like toast. Donna couldn't tell. All she knew was that the Doctor kept smacking it, shaking it, and muttering evil-sounding things to it under his breath.

"Oi!" said Donna. "What did that toaster ever do to you?"

"It's not a toaster, it's — oh, never mind," said the Doctor. He gestured for her to come over, and she noticed a series of bleeping numbers appearing on the side of the toaster. He pointed at them. "This is telling me that we're at the locus of the interference matrix already, but I know this town, and there's nothing out of the ordinary. Which means the psychic augmentation detector is giving us faulty readings."

"Oh, well that's just blooming fantastic," said Donna. "We're looking for Excalibur — in California — and your toaster isn't working. End of the world, that is."

"End of the universe, more like," said the Doctor.

Donna frowned. "What, are you serious?"

The Doctor glanced up at her, and Donna could tell, in an instant, that he was.

"So we're looking for a mystical sword that isn't actually a mystical sword, and if we don't find it, the universe is going to end?" Donna asked.

"Could do," said the Doctor. Then he hit the toaster again, and shook it. "It's not working," he said. He sat down on the curb, dug his sonic screwdriver out of his coat pocket, and started buzzing at the toaster. "Why don't you look around and see what you can find?"

"See what I can find?" asked Donna. She crossed her arms. "I've never been here before, Spaceman! How am I supposed to know if something's just popped into existence?"

"Ask someone," said the Doctor, obviously too preoccupied with his toaster to register what he was saying.

Donna gave him her best defiant stare, but it was obvious that the Doctor couldn't understand why this particular brilliant plan of his was doomed to failure. Donna sighed, and marched off to the nearest door in sight, knocking on it with all the professional manner she'd acquired over her many years working in offices.

The door opened, and there, standing behind it, was a petite blond woman wearing a pink halter-top and dark navy shorts. She looked about 20, but her poise and determination spoke of a wisdom far beyond her years. "Hello?"

Donna put on her best smile. "Hi, Donna Noble. You haven't, by any chance, seen a sword that doesn't look like a sword and doesn't act like a sword, have you?"

"Huh?" asked the woman. "Wait, you're looking for a sword?"

"Yes," said Donna.

"But it doesn't look like a sword or act like a sword?"

"Yes."

"So… what does it look and act like?"

"No idea."

The woman nodded, slowly. "Okay. So, this might sound like a dumb question, but if I don't know what it looks like, how would I know if I've seen it?"

"Beats me," said Donna. She looked over her shoulder at the Doctor. "Oi! Spaceman!" she called. "I told you this wasn't going to work!"

His head jerked up, the screwdriver slipping a little in his hands, and there was a loud bang as the toaster exploded, cogs and wires flying through the air. The Doctor emerged from the cloud of debris, putting his sonic back into his coat pocket.

The woman looked over Donna's shoulder, and sighed. "I should have guessed," she said. "This has Doctor written all over it." She waved at the Doctor, and he waved back, a little awkwardly.

"Hello, Elizabeth," said the Doctor, walking towards them. "Thought this street looked familiar."

Donna gawped, her eyes darting between the Doctor and the petite woman. "You two know each other?"

"It's a long story," said the woman — Elizabeth?

"And you're… Elizabeth," said Donna.

The woman offered Donna her hand. "It's Buffy, actually. Buffy Summers. He's sort of the only one who's allowed to call me Elizabeth."

Donna shook the hand. She thought that the name Buffy sounded like something you'd call your cat and not your mate, but who was she to argue? "Donna Noble," said Donna, even as she realized she already had.

"So _you're_ Donna," said Buffy. "Huh. Go figure. I always wondered what you looked like." She glanced over at the Doctor. "This is pretty early in your timeline for you, isn't it? You haven't even done the whole Trio of Hell thing yet."

"Nope," said the Doctor.

Buffy leaned against the door frame. "So, why are you in Sunnydale? Is the world coming to an end again?"

"Oh, just looking for something," said the Doctor. "Bit of a quest. Actually, you might be able to help. Temporally aware and all that. We're trying to find—"

"Look who's showed up again," came a teenage voice from inside the house. Donna watched as a skinny teenage girl approached the door. "Your secret boyfriend."

Buffy turned. "Dawn, he's not my boyfriend!"

Donna was more interested in the Doctor, who had frozen right where he was, staring, open-mouthed, at Dawn. There was a trace of something in his face — disbelief? Shock? Horror? Sorrow? — all overshadowed by a sudden, terrible loneliness. Seriously, she'd give a hundred pounds just to figure out how Skinny's brain worked, sometimes.

(Or was he just missing the family he could never have?)

Buffy pushed Dawn away from the door, and turned back to the Doctor. "Sorry about that," said Buffy. "You know how sisters are."

"Sisters," breathed the Doctor. "You… have a sister."

"Yeah, Dawn," said Buffy. She frowned. "Actually, have you met her, yet? I mean, she's met you, but I think she's only met future yous." Buffy hesitated, and glanced back over her shoulder. "I should probably talk to her about the whole not-revealing-personal-future thing before I introduce you." She backed up, and opened the door. "Oh, um, will you come in? It's, I mean, my mom's out, so it's just my sister and me, but I'm happy to help with this quest thing you're on."

The Doctor blinked, a mask of happy indifference crashing across his face. "Help," the Doctor muttered, as he entered the house. "Yes. Could use that. Certainly could use that. Bit of help all around, I should think."

Buffy led them into the living room, gesturing for the Doctor and Donna to sit down on the couch. "So, you said you were looking for something? A sword?"

"What? Oh, no," said the Doctor, sitting down. Donna sat beside him. "Sort of — bit of a wild goose chase. Not really that important, anyways."

Wait, that wasn't right. What about end of the universe? Donna turned on the Doctor. "Doctor, I—"

The Doctor cut her off with a warning arch of his eyebrow. Donna looked back at Buffy, then at the Doctor. And it hit her, all at once, that he'd already found the thing he was looking for.

Donna hadn't seen any swords or anything, though. So she wasn't really sure what the Doctor had found that made him so jumpy.

"Oh, come on," said Buffy. "I'm up for a little seek and discover thing. What are you looking for?"

"Excalibur," said the Doctor. "Just, you know. What with Morgaine trying to detonate an atomic bomb in the English countryside three years ago and all."

"You mean Morgan Le Fay?" asked Buffy. "From the Arthurian Legends?"

"I'm her arch-nemesis," said the Doctor. "Merlin, that's me. Will be me. Bit acausal, but still works."

" _You're_ Merlin?" Buffy laughed. "Willow is going to be so pissed off when I tell her."

"Oi!" cried the Doctor. "I'm going to be a great Merlin someday."

"And your sonic screwdriver is your magic wand!" Buffy cried, laughing even harder. She collapsed onto the couch beside the Doctor — a little bit closer than Donna thought was appropriate for two 'just mates'. The Doctor didn't seem to mind in the slightest — although he did give a theatrical little pout at her laughing at him. "Oh, you have _got_ to take me to Camelot when you go there. I so want to see you all magicky and stuff with your sonic screwdrivers and your atomic bombs and everything."

The Doctor's mask dropped a hair, and for a moment he seemed very, very sad, and incredibly lonely. A sort of terrible doomed sort of look, as if the Doctor were condemned to die, and merely waiting for the time when it would happen. Buffy was laughing too hard to notice. But Donna noticed. Two seconds later, the mask was back in place, and the Doctor was back to looking at Buffy, indignantly.

"Three years ago?" Donna asked the Doctor. "You mean we're here looking for something you last saw three years ago? Why didn't you pick it up then?"

"It was more than three years ago for me," said the Doctor. "And besides. I was a wee bit busy averting a nuclear holocaust."

"Morgan La Fey, powerful witch and sorceress," Buffy mused, her laughter dying down into giggles. "You know, I can't picture her being all atomic bomby."

"Course she was," the Doctor protested. "I should know; I was there. Demons, bombs, interdimensional bits, the whole nine yards. You think nothing happens outside of Sunnydale?"

"You. Are. Bonkers," said Donna.

"Oi!" said the Doctor. "That's all true, that is. Completely 100% factual. If you don't believe me, you can ask Alistair. He was there, too."

Buffy shot the Doctor a slightly flirty grin. "I could totally see you doing that. Mr. Magic Merlin Guy."

"I think he makes half of it up," said Donna, leaning back against the sofa cushions.

"So, what's Excalibur like?" Buffy asked the Doctor.

"Sorry?"

"Well, you said it was a sword, but it didn't act like a sword or look like a sword, so what does it act and look like?" Buffy asked.

"Could look like anything," said the Doctor. "And as for what it does, well, that's sort of a bit… technical. Best just say, in the wrong hands, might be a wee bit catastrophic."

"End of the universe?" asked Buffy.

"Something like that."

"You do universe-ending catastrophes like I do apocalypses," said Buffy. "This should be old hat to you."

The Doctor shrugged. "Should be."

Buffy tucked her knees up on the sofa. "So, you're on a quest," she said. "To find Excalibur. And save the universe."

"Yep," said the Doctor.

"And you're looking in California because…?" Buffy examined the Doctor, carefully. "Let me guess. You were aiming for England in the Middle Ages, but for some crazy reason that has nothing to do with the fact that you're a lousy driver, you wound up in California, 2000 instead?"

Donna opened her mouth to negate this, but the Doctor cut in, first. "Yes!" he said to Buffy. "I mean, no! I mean, well, meant to land here all along, really. Nothing to do with faulty navigation."

Buffy laughed. "Admit it," she said. "You're not here for the sword. You're just here to see me, again." She gave him a very wide grin.

And he met her smile with his own. Their eyes locked, almost twinkling as they sat there, far too close together, staring at one another, almost trying to pass some sort of nonverbal communication.

Donna wished they'd stop with the lovey-dovey faces and just start snogging already. Seriously. The sexual tension was so thick, you'd need a bloody chainsaw to slice through it.

"I want to hear about Excalibur," Dawn complained, as she entered the room. "I don't understand what's so secret about this meeting, anyways. It's not like you're talking about anything that important."

Buffy looked away from the Doctor, her eyes snapping over to her sister. A look of complete frustration passed across her face, as she tried to keep calm. "Doctor, Donna, will you excuse me a moment, please?" she asked, getting up from the couch.

She then dragged her sister out of the room, up the stairs, and slammed a door behind them.

Donna turned on the Doctor. "Doctor, I thought you said—?"

The Doctor shushed her, listening carefully. The moment he heard Dawn and Buffy's muffled voices echoing through the household, he whispered to Donna, "I should have known this was going to happen."

"What?" asked Donna.

"Remember, on the TARDIS, I told you that segments of the Key to Time could be disguised as anything, anything at all?" the Doctor asked. "Thing is, that's not entirely the truth. They can be disguised as anything… or anyone."

Donna thought back to the way that the Doctor had reacted to Dawn, the way he'd stared at her. The way he'd asked Buffy about her sister.

"You don't mean…?" asked Donna, but she was sure that was exactly what he meant. "No."

"Elizabeth is an only child," said the Doctor. "She doesn't have a sister. I've seen her in two timelines, and she's never had a sister." He ran a hand through his hair. "Oh, I'm so thick! I should have seen this a mile off. They knew I was going to destroy it. Those monks, they knew that the moment they created another segment, I'd track it down and get rid of it. They were ready for me."

"It's… that girl?" asked Donna.

"Yes."

Donna shook her head in denial. "No, no," she said. "You're wrong. She's just a kid. And you said your toaster was giving you faulty readings."

The Doctor hung his head. "I don't need a psychic augmentation detector or a tracer. I can see it, Donna," he said. "Plain as the nose on your face. The segment to the Key to Time — it's her. Dawn Summers. Those monks transformed the energy into a person — an innocent little girl." His grip on the couch cushions tightened. "Just one more innocent victim."

Donna felt sudden horror wash across her, as she realized what the Doctor was saying.

"Doctor, you can't—" Donna began.

The Doctor's head shot up. "And if I don't, then what?" he demanded. His face was stony, his gaze icy, and he was the same Doctor who'd terrified Donna when she'd first met him. "There are no other Time Lords, Donna. If that energy ever gets loose, if that portal opens, there will be no way to stabilize it. Every wall encircling reality will collapse. The entire multiverse will blend together, every universal law will be overwritten. And if we live through that, if that doesn't mean the end of the universe, then the Time Lock will snap, and the entire time vortex will be destroyed. Do you understand, Donna? Do you understand what's at risk?"

In the background, Donna could hear Buffy and Dawn talking to one another, in stern voices. Donna felt a terrible sorrow, hearing them bicker like that. They sounded so much like normal sisters, it was hard to imagine that they hadn't been that way forever.

"She's an innocent person," said Donna. "She's just a child. Please, Doctor. You can't."

The Doctor massaged his forehead with his thumb and index finger, but said nothing.

"We can take her with us," said Donna. "She'll be safe in the TARDIS."

"She won't," said the Doctor. "She can't leave this solar system, Donna. Dawn Summers is inherently unstable — the seventh segment of a six-segment Key. Any fluctuations in the energy she's carrying, and cracks could appear. And I will not be responsible for letting any more Daleks into this reality. I will not do that."

Donna stared at the Doctor. "Does she even know what she is?"

"No," said the Doctor. "The Princess Astra didn't, not until the preassigned point in space and time when everything converged. Dawn won't, either, and neither will Elizabeth. No one here knows anything about the danger they're in. And if anyone knows, the energy will be unleashed, and the universe will be destroyed."

"So don't tell them," said Donna.

The Doctor shook his head.

"Oi, listen to me, Spaceman," said Donna. "It's not like she could just Orbitz up a flight out of the solar system or anything. And if no one except me and you know what she really is, no one knows enough to unleash the energy."

There was a small flicker of hesitation in the Doctor's eyes. That was a good sign.

"I couldn't," the Doctor decided. "I couldn't take the risk."

"She's an innocent child," Donna insisted. "You can't kill an innocent human child!"

The Doctor just stared down at his hands. His expression was dark, hopeless, thoroughly dangerous and desperate and angry.

"What's one more?" he muttered.

Buffy and Dawn emerged in the doorway, and Donna sprang to her feet. She didn't know what the Doctor meant by that last comment, but she knew she wasn't going to let him do something like this. She hadn't, back in Pompeii, and he'd told her she was right. So she wasn't going to let him do it, now.

The Doctor looked up, a carefree smile back on his face. He got up off the couch, looking so innocent and friendly and harmless, it was… creepy. Spooky.

Neither Dawn nor Buffy seemed to realize anything was wrong.

"Okay," said Buffy, trying to reassure herself more than those around her. She looked over at the Doctor. "Doctor, this is my sister, Dawn. Dawn, this is the Doctor." She then added, in a more pointed tone of voice, "who hasn't met you yet."

"I know," snapped Dawn. She went over to the Doctor, awkwardly, one hand in her jeans pocket. She gave the Doctor a little wave. "Hi."

"Dawn," said the Doctor, giving her a charming smile. "Lovely name. Dawn. Never met a Dawn before. Met a number of Elizabeths, but never any Dawns. Well, almost never." He extended a hand to her. "I'm the Doctor."

"And I'm Donna," Donna cut in. She barged over to the trio, and tried to insert herself between the Doctor and Dawn. "And, no, maybe I'm not an alien, but I'm every bit as important as Skinny, here, I'll tell you that."

"Hi," said Dawn. She seemed less than enthused. Fine with Donna. As long as she didn't get killed, anything she did was fine with Donna. Except that whole blowing up the universe thing. That was less fine with Donna.

"So, Dawn," said Donna, "tell us about yourself. What sort of things do you like?"

The Doctor arched an eyebrow at Donna, but she ignored him. The Doctor didn't kill people — not like this. Maybe if the Doctor saw Dawn as a real person, and not a sword, then the Doctor wouldn't be able to kill her.

"I don't know," said Dawn. "I guess I sort of like magic and stuff. You know, like Willow and Tara do. That's pretty cool."

"What, magic's real?" Donna asked. She turned to the Doctor. "You going to take me to Hogwarts next?"

"Oh, my God, you've read that?" Dawn asked. She looked over at Buffy. "See? I told you they weren't books for babies."

"Are you kidding me?" Donna said. "I loved them. Oh, and that bit where Sirius Black—"

"Donna," the Doctor warned.

Donna swung around and gave him a long, angry glare. The Doctor's calm external mask faltered, just a hair. This time, Buffy seemed to notice. She frowned.

The Doctor put his mask back into place, and stuffed his hands into his pockets. "Nothing past the third book," he told Donna. Then he turned, and strode out of the living room.

Buffy looked from him to her sister and Donna. Buffy had clearly picked up on something. And… well, the Doctor obviously cared about Buffy quite a lot ('just mates?' Ha!). And Dawn _was_ her sister…

"You better go after him," Donna told Buffy. "He's in a right snit, now."

Buffy looked over her shoulder, at where the Doctor had disappeared, then back at Dawn. "Don't do anything stupid," she warned Dawn, then ran after the Doctor.


	3. Chapter 3

Buffy rushed out of the house, and, spotting the tan trench coat down the street, darted after it. She caught the Doctor by his arm, and he glanced over his shoulder at her. His face still looked mildly cheerful, vaguely amused, completely normal. But his eyes… there was something wrong in his eyes. Buffy could see that.

"What's wrong?" she asked.

"Nothing," said the Doctor. He started walking, again — a casual, easy stride. "Absolutely nothing. Well, trying to find a mythical English sword in California, but aside from that, nothing at all."

Buffy matched pace, beside him.

"It was Dawn, wasn't it?" she asked. "She's already said or done something that's told you something about your own future, and now you're—"

"Buffy," the Doctor interrupted. "I'm fine. Nothing bothering me. Nothing the matter. Just need to be alone."

Buffy felt her heart pounding a little louder. "You called me Buffy."

"Well, that is your name," said the Doctor.

Oh, wow, this was a _really_ young version of him! He didn't even know about _that_ , yet? "Doctor, when you call me Buffy, I pick up stuff from you," Buffy explained. "You know. Telepathic stuff. Emotions and things."

The Doctor froze. "Sorry, you what?"

"I pick up telepathic — wait, why don't you know this?" Buffy asked him. "You've always called me Elizabeth instead of Buffy, even at this point in your personal timeline."

The Doctor turned to face Buffy. "Well, you asked me to," he said. "Not… yet, I mean. In… your future." He cleared his throat, and straightened his tie, his face melting into guilt. "What… did you pick up, exactly? When I said your name?"

"Worry," said Buffy. "Disbelief. Sorrow. Anger. All of which means I'm probably right." She sighed. "Look, I wasn't good at this, either, when I first met you, remember? I kept trying to resume conversations you hadn't had yet. But you gave me a chance, and I got better. Give her a chance, and Dawn will, too."

The Doctor examined Buffy, carefully. Then, in a voice barely above a whisper, he breathed, "You love her."

"She's my sister," said Buffy. "I mean, yeah, she thinks she's the center of the world, and yeah, she annoys the hell out of me, but I still love her."

The Doctor said nothing for a long moment.

"Doctor," said Buffy. "If there's something wrong—"

"Why do you trust me?" the Doctor asked her. His voice had suddenly shifted from lighthearted and carefree to dark, edgy, dangerous. Any trace of happiness fell off his face, and all that was left was a raw, bitter anger tinged with sorrow and guilt.

Buffy frowned. "Huh?"

"Angel knew me far longer than you," said the Doctor. "And he knows enough not to trust me. You claim you've met future mes. You clearly know me well enough to know who I really am and what I've done. What I could do. So why do you keep trusting me?"

Buffy crossed her arms. Great. So this was an other-her thing. "You're not going to destroy my life," she told him. "You know why? Because I'm not going to let you."

The Doctor raised an eyebrow.

"You're forgetting," said Buffy. "I'm the Slayer. Anything I don't want doesn't happen."

"Two-thirds of the population of this planet is going to die over the next century," said the Doctor. "All children. All innocent. And you won't be able to stop it. Because I killed them. Did you know that?"

Buffy blinked at him, confused. That figure sounded familiar to Buffy, from… oh, that's right. When she'd first met him.

"Omega said that," Buffy said. "But, I mean, that was about the vampire thing. With the First. And I fixed that. The First didn't get you. You're not a vampire, you're not going to kill—"

"I already have," the Doctor told her. "It's in my past. That's how I know you can't stop it. Because you didn't."

Buffy didn't know what to say to this.

"Stop trusting me, Elizabeth," he said, turning to go. "Because from now on, I am your enemy."

Buffy grabbed him by the back of his coat, and dragged him back to face her. "What are you doing?" she demanded.

The Doctor said nothing.

"Is this a guilt thing?" asked Buffy. "Because I'm done with the guilt thing. Not everything in the universe is your fault."

The Doctor extricated himself from her grip on his coat. "I'm just letting you know it's me," he said, "so that, after it happens, you don't blame anyone else."

"After what happens?"

The Doctor just gave her a hard stare, then continued to walk off.

Buffy caught his arm, and spun him around to face her. She gripped him by his forearms, holding him in place.

"After what happens?" she said. "What are you going to do?"

"What I have to," said the Doctor.

And Buffy could tell by the harsh look in his eyes, by his cold demeanor and his stance, that it was something he really, really didn't want to do. Something she really, really wasn't going to like.

"No," said Buffy.

"You can't stop me."

"I could always stop you," said Buffy. "I just don't like to do it by force."

"Then stop me."

Buffy felt a chill run up her spine as she heard those words. The words she would repeat to him, in her past but his future. She loosened her grip on his arms, and he pulled away from her.

"Tell Donna I'm sorry," said the Doctor. "I had to do it. I have no other choice."

"Had to do what?" Buffy asked. "What are you going to do?"

The Doctor turned, and headed off down the street, his hands tense by his sides, his jaw set, his eyes blazing. "One of the worst things I've ever done," he said.

Buffy ran in front of him and pushed him back. He caught himself before falling.

"Not good enough," she snapped.

She reached out to grab him and hold him in place, but he caught her wrists in his hands, and stared into her eyes.

"This," said the Doctor, through his teeth, "is the day you will hate me forever. This is the day you'll curse my name, and decide that you want nothing more than my head on a platter. This is the day that I become your greatest enemy. And I have no choice. Because some thick, imbecilic humans decided to mess around with forces they don't understand, and now I have to do something that will make me hate myself. And I'll do it. Because I've done it before. Because what's one more innocent life? What's one more death on my head, after I've murdered so many others?"

Buffy just stared at him. "What's wrong with you?"

The Doctor dropped her hands. "Everything." He turned around, and started walking away, again. "If it means anything, I'm sorry about this."

"Yeah," said Buffy. "Me too."

And in one swift movement, Buffy knocked the Doctor across the head, so that he dropped, unconscious, to the ground. She stared at him, a moment, trying to digest what had just happened. What he had just told her. He was going to kill someone. One innocent life. And whoever it was, Buffy knew them. Whoever it was, Buffy would want to kill the Doctor for doing it. Buffy still didn't understand exactly what was going on, but she was sure of one thing.

The Doctor had landed exactly where and when he'd wanted.


	4. Chapter 4

"Why'd you have to knock out Donna?" Dawn asked. "I liked Donna."

"I don't think she knows anything," said Buffy, tying a long, thick rope around the Doctor's arms and torso. "But she'll untie the Doctor. And he needs to stay tied up."

"Because?" asked Dawn.

"Because he said he was going to murder one of my friends," said Buffy.

"And you believed him?"

"When he talks like that, I believe him," said Buffy. "Whatever this Excalibur thing is he's looking for, it's bad. I'm talking seriously bad. Worse than killing off two-thirds of the world bad."

"And you're stopping him from getting rid of it?" asked Dawn.

"I'm stopping him from going crazy and killing someone he shouldn't!" Buffy snapped. "He's not thinking straight! He…" The rope shook in Buffy's hands, as she looked at the Doctor's unconscious face. "He wouldn't do that."

"I still don't get why Donna has to be tied up," Dawn muttered. "She's human. She can't do anything."

"If you'd met any of the Doctor's other companions, you'd know that's not true," said Buffy. "I've seen Martha talk a vampire out of killing her. Amy managed to get rid of that super-evil slime demon thing a few months ago. Jack can die a thousand deaths and still manage to come back to life. And, if you believe the Doctor, Rose turned an entire fleet of Daleks to dust with her mind. Trust me. The Doctor's companions aren't as helpless as you'd think."

Buffy tied the knot on the rope that bound the Doctor's arms and torso, shifting him so that he lay in the center of the bed. Dawn thought she was being incredibly diplomatic by _not_ pointing out to Buffy that she was tying up the guy she was head-over-heels in love with in her bedroom. On her bed.

"You tied that way too loose," Dawn pointed out, instead. "He's going to get free."

"Just tie up Donna, okay?" Buffy snapped.

Dawn flinched back at Buffy's sudden anger. She watched as Buffy took a deep breath, as if preparing herself to do something painful, then yanked on the ropes. The Doctor gasped for breath. Buffy's eyes widened, and she quickly loosened the ropes a little, before tying the knot again. She looked at the Doctor's unconscious face, and took a few deep breaths, trying to get herself together. She shook her head, grabbed the other bit of rope that she had gotten out of the basement, and started tying his legs together.

Dawn, meanwhile, began to secure Donna.

"Tie her to the chair," Buffy instructed, pushing a desk chair over to Dawn.

"You're not tying the Doctor to a chair," said Dawn. "You're just kind of putting ropes around him."

"Just do it!" Buffy snapped.

Dawn rolled her eyes. "Pushy much?"

Dawn started retying the ropes, so that they circled around and through the back of the chair. It was only when she realized that Buffy hadn't answered or even acknowledged she'd said anything that Dawn thought maybe there was something really, really wrong. She looked up at Buffy, who had stopped, just staring ahead, at nothing, rope still in hand.

"I said, pushy much?" Dawn repeated, trying not to let the fear come through into her voice.

"I heard," said Buffy.

Dawn frowned. "Buffy, you can stop him, right?" she asked. "I mean, you're the Slayer, and he's just some… alien."

"It's not that," said Buffy. "I can stop him. It's just… how that's the issue."

"Well, you're going to tie him up," said Dawn, "and then you and I are going to go out and find Excalibur, and—"

"You're not coming," said Buffy.

"Why not?" asked Dawn, tying the final rope around Donna, and knotting it off.

"Because I think he might be right," said Buffy. She squeezed her eyes shut. "And in the end, I'm the Slayer. It's my job. Not his."

Dawn's eyes grew wide, as she realized what Buffy was saying. "Hang on," she said. "You're saying that you are going to find Excalibur first, and… kill whoever has it? Even if it's one of your friends?"

"I'm going to find another way," Buffy insisted. "One that allows everyone to live. But if I can't, if there's no other alternative…." She took a deep breath. "I'm the Slayer. It's what I have to do."

"You're prepared to kill Willow, or Xander, or Tara, or Giles, or—"

"It's not them," said Buffy. "I know who has Excalibur. There's only one person it could be." She gave a humorless laugh. "And I was so stupid not to see it before."

"Who?" asked Dawn.

Buffy looked over her shoulder at her sister. "It's Riley," she said.


	5. Chapter 5

Dawn's eyes widened. "Your boyfriend?"

"It has to be," said Buffy, as she tied off the knot of the rope around the Doctor's legs. "All the pieces fit. The way Riley's been acting recently — all weird and erratic and stuff. The way he keeps looking at me, like there's something he wants to tell me but just can't. And the way he always wants to impress me. If he got his hands on some big powerful weapon, something that could make him superman without my knowing about it, he'd do it. In a heartbeat. And… this Doctor's young enough that I don't think he's met Riley, yet." She shook her head. "The Doctor told me — the day he met Riley, Riley tried to kill him. Now I know why."

"Uh, yeah," said Dawn. "Because Riley is totally jealous. Buffy, are you blind?"

"Riley's the one friend I have that I wouldn't be able to forgive the Doctor for killing," said Buffy. "Ever. And he knows it. And Riley would never hand Excalibur over to the Doctor, not in a million billion years. Maybe… if I'm lucky, maybe Riley will hand it over to me."

"I thought you said you didn't know what it looked like," Dawn pointed out.

"I don't," said Buffy. "But I called Giles, and he's finding out everything he can about Excalibur." She felt in the Doctor's coat pockets, and frowned. "No sonic," she muttered. "He must have hidden it somewhere on him." She started patting him down, trying to find any hidden devices he might have on him.

Dawn couldn't help but notice that Buffy's hands lingered a little too long, when she was searching the Doctor. And she seemed to enjoy it just a little too much when she had to pat down more sensitive areas.

"And you say you're just friends," said Dawn.

"If he has the sonic on him when I leave, he'll be out of here in five seconds," said Buffy. She swore. "I can't find it." Then her eyes fell on the wooden chest by her bed, and she had a sudden brainwave idea. "Wood," she realized. "It doesn't work on wood." She picked him up, and started dragging him out the door. "Dawn, grab Donna. We're taking them to the basement."

"To the… you just made me tie her to the chair in here!" Dawn said.

"I changed my mind!" Buffy replied, as she slipped out the door with the Doctor.

Dawn, after a lot of untying and a large amount of dragging, managed to get Donna partially out of the room. Buffy ran up to grab Donna, and nearly sprinted with her back to the basement. Dawn decided that Buffy did way too much running. She huffed as she trudged down the two flights of stairs, and into the basement.

The Doctor was already down there, bound and lying on the floor — and still not secured to a chair, Dawn noted, just lying there. Buffy had placed Donna on a chair, but was now sitting beside the Doctor, again. Yep. Doctor lying down, bound and helpless, Buffy stroking her hand through his hair — she was definitely not at all in love with him.

"You know, I can see why Riley has no reason at all to be jealous," Dawn said.

Buffy sprang to her feet, stepping away from the Doctor. Her face went red, and she shifted, guiltily. Dawn had a feeling she wasn't supposed to have seen what she'd just seen. Buffy forced her face to go back to normal, then looked up at Dawn. "Did you bring the rope?"

Dawn climbed down the stairs and handed Buffy the rope. Buffy looped the rope around Donna and the chair, tying her hands and feet together, hastily.

"Admit it," said Dawn. "The only reason you didn't just tie them up here in the first place was because you loved the idea of tying up the Doctor in your bedroom."

"I'm just trying to save Riley's life," said Buffy, not even looking at her sister. "That's all."

Uh-huh. Sure.

"Buffy, let me summarize the situation, here," said Dawn. "You tied up the Doctor, the guy you're totally in love with even though you won't admit it. In your bedroom. On your bed. To stop him murdering your boyfriend. And you know it's your boyfriend he's out to murder, because your boyfriend tries to kill the Doctor the day the Doctor meets him. A meeting that, apparently, has everything to do with a magical sword, and nothing to do with the fact that it's the Doctor you fantasize about tying up in the bedroom, and not Riley."

"Better summary," said Buffy. "There's something really bad out there that's going to destroy the universe. The Doctor's going to kill the person who has it, and I have to make sure that I find it before the Doctor does, or before the universe goes boom." She finished securing Donna, and got up.

"Face it, Buffy," said Dawn. "Soap operas have nothing on your life."

"Dawn," said Buffy, with a sigh. "Shut up."


	6. Chapter 6

"You have got to be kidding me!" Donna shouted, as she struggled against the ropes. She looked over at the Doctor, who was just staring straight ahead, not doing anything clever or spacemanny. "Oi! This is your fault, isn't it?"

The Doctor glanced back at Donna, but said nothing.

"What'd you do?" Donna demanded. "Tell her all your plans?"

"I told her I was sorry," the Doctor replied. "She worked it out."

Donna stopped struggling. Her only argument to convince the Doctor not to go through with this had been the fact that Dawn and Buffy didn't know. If Buffy had worked it out, Donna wasn't sure she had anything else that would stop the Doctor.

"How much?" she asked, quietly.

"Not who," said the Doctor. "At least, not yet."

Donna could see, from the dark expression on the Doctor's face, that he hadn't changed his mind about this. The ropes were no obstacle — he'd get free eventually. And Donna didn't want to know what would happen if he got free. She didn't want to think about it.

"Doctor, you can't," she pleaded. "She's an innocent human girl."

"She isn't real."

"She's as bloomin' real as you or me," Donna insisted. "Oi! Listen to me, Sunshine. I don't know what you consider real on planet Time Lord, but here on planet Earth, any human being, even one who's actually a mystical sword in disguise, is a real human being."

The Doctor didn't answer.

"I've been talking to her," Donna insisted. "She's shown me her diaries dating all the way back to when she was seven. She's a real person. She has real dreams, real hopes, real thoughts, real fears. She even has a secret crush. How can you say she isn't real?"

"You can't see it, Donna," said the Doctor, softly. "What she really is. I can."

Donna struggled against her restraints again, but they didn't give. "You know what I think?" Donna asked. "I think you don't want to admit she's real. Because if you ever admitted she was real, I don't think you could ever go through with it."

The Doctor wouldn't meet Donna's eyes. "I've done it before."

Donna didn't think she wanted to know that. "When?"

The Doctor didn't answer.

"Doctor," said Donna. "Think about this. So she's a sword. She doesn't know she's a sword. She doesn't look like a sword. She doesn't act like a sword. So what makes her a sword?"

The Doctor said nothing, but Donna thought she could see the slightest bit of hesitation. He was trying to talk himself into doing it. Donna was sure of that. The Doctor might be terrifying, at times, and he might let terrible historical events happen, even when they meant the death of an entire city, but that didn't mean he felt good about it. She had to play up every doubt he had, or he'd go through with it. And Donna couldn't let him go through with it.

"No one needs to find out," Donna continued. "And maybe we can't take her with us, but we could drop by and check on her. We could make it work."

The Doctor said nothing.

"Doctor—" Donna started, but the Doctor shushed her. He seemed to be listening. Donna listened, too, and could hear muffled talking from upstairs.

"They're talking about Excalibur," said the Doctor, in a quiet voice. "Trying to work out what it is."

"Is that bad?" asked Donna.

"If Elizabeth's clever enough to work it out." The Doctor began squirming around in his bonds, like a writhing seal.

"And is she?" asked Donna.

"Oh, yes."

* * *

"Well," said Giles, taking off his glasses. "From what I've discovered, it appears Excalibur was last seen in England. We might be able to trace it from there."

They were sitting around in the dining room of Buffy's house, Giles surrounded by a large stack of books he'd taken over, all to do with King Arthur and Excalibur. Buffy had nailed wooden boards in front of the basement door and windows, and she was fairly certain that would keep the Doctor contained. Assuming her mother didn't kill her for doing it.

"Yeah, if you're proposing a séance with King Arthur, I'm pretty sure that's not going to work," said Buffy. "That was, like, a bazillion years ago, Giles. Excalibur could be anywhere, now."

"Only three," Giles corrected.

"Three what?"

"Years," said Giles, sliding his glasses back onto his face. "Since Excalibur was unearthed, I mean. Somewhere outside of Carbury, it seems, by an archaeologist named Peter Warmsly. It all happened round about the time that the Master was trying to open the Hellmouth, here, so I was a little preoccupied, but it does seem this Excalibur nearly destroyed the world."

"Yeah, the Doctor mentioned that, right?" said Dawn. "Like, nuclear bombs and stuff. I remember."

"Dawn," Buffy sighed, "get out of here."

"What?" said Dawn. "I'm trying to be helpful."

"No, she's quite right," Giles agreed, flipping through one of the books, and then displaying its contents to Buffy. "It appears that Morgan La Fey, using Excalibur, managed to summon a terrible demon known only as 'the Destroyer', and nearly destroyed the world with a nuclear warhead. She was stopped by her arch-nemesis, Merlin, who disappeared without a trace shortly thereafter."

"Until he showed up here, and Buffy decided to tie him up on her bed," said Dawn.

Buffy ignored her. "Okay, so what did Excalibur look like? I mean, this picture, here — it looks like a sword."

"Well, it's said this particular relic was actually from another reality," said Giles. "And much speculation has been made that there is a matching relic originating in this reality. One which performs the same function, but takes on a different shape. That is probably the item you're looking for."

"And that function would be…?" asked Buffy.

Giles opened another book, and thumbed through the pages. "Well, I believe that Excalibur wasn't actually a sword," he said. "It looked like a sword, but it served some other purpose."

"Yeah, got that," said Buffy. "It's some super-weapon, or something, and it can blow up the universe. I'm just trying to work out how."

"Actually, I'm not certain you're correct about that," said Giles. He flipped to the page he wanted. "See, here, in Peter Warmsly's notes. 'It was at this point that the UNIT advisor, whom I shall refer to in this text simply as Merlin, explained to us that Excalibur was not really a sword at all, but a key.'"

Buffy and Dawn looked at one another, both lost. Buffy turned to Giles.

"Huh?" she asked.

"It appears that what you're looking for is not a weapon," said Giles. "It's a key."

"A key?" asked Buffy. "You mean, this thing that's made the Doctor turn from hard-core-pacifist to potential-murderer is a _key_?"

"It could be a really deadly key," Dawn offered.

"It's a key!" Buffy said. "Keys aren't deadly! Keys are just… keys! They aren't even dangerous!"

"I'd have to point out," said Giles, "that a key is only as dangerous as the thing it's keeping locked up."

And the Doctor had a ton of bad things he'd probably want to lock up. A huge, huge number of things. She thought she remembered… something… a spark of conversation from way back when she first met the Doctor... a conversation that had mentioned something important about a key, but when she tried to grasp the memory, it was fuzzy. Unobtainable. Okay, that was weird. Maybe the Doctor hadn't mentioned anything about a key, and Buffy was just misremembering.

"Okay, first it's tying to the bed, now we've got keys and locks and stuff," said Dawn. "I don't know what kind of bondage thing you guys have going on, but if the next ancient artifact the Doctor hunts down winds up being something even more kinky, I'm pretty sure you should take that as a sign."

"Dawn, shut up," said Buffy. To Giles: "This Excalibur-equivalent artifact — does it, like, attach itself to someone, or something? Get inside their heads and manipulate their thoughts? Or does it bind with their skin so you can't get it off? Or — oh, does it turn them into a demon? Steal their souls and stuff?"

"Not that I'm aware of," said Giles. "Excalibur itself didn't do anything of the sort. Why?"

"The Doctor wouldn't say he was going to kill someone unless there was absolutely no other way," said Buffy. "The kind of artifact you've described — the Doctor would just take it and leave. No killing involved at all. If he's talking about killing people, there has to be something more to it than that."

Besides which, if Excalibur turned its victims into something nonhuman, it meant Buffy could kill them. And if she needed to kill someone, she really, really wanted them to be a demon. She wasn't sure she could go through with it, if they were human.

"Well, I can certainly look into it," said Giles. "If you're sure that there's some other aspect to this artifact that we've overlooked."

"I'm sure," said Buffy.

"In the meantime, if this Excalibur artifact does have some sort of hold over its victims, it's essential that we keep an eye on all potential victims at all times," said Giles. "They might not even know that they are under its influence."

"Plus, the Doctor's going to show up wanting to kill them," said Dawn.

"Have you informed Riley of the situation, yet?" Giles asked Buffy.

"I called him up," said Buffy. "He insists that he hasn't picked up any weird objects or anything recently. But, I mean, if there's some sort of mind control thing going on, then he wouldn't tell me, anyways, would he?"

"And Riley certainly has been acting rather oddly of late," Giles agreed. "I've noticed that as well. Did you warn him about the Doctor?"

"I told him to be careful that someone might be out to kill him," said Buffy. "I didn't say who it was."

"So… you've just made the guy we know is going to try to kill the Doctor at some point in the near future supremely paranoid?" Dawn asked. She rolled her eyes. "Talk about a self-fulfilling prophecy."

"Riley isn't going to try to kill the Doctor," Buffy insisted. "He doesn't even know the Doctor is the one trying to kill him."

"I bet he works it out," Dawn muttered.

"Giles, is there any way we could actually detect this sword-key-thing?" asked Buffy, ignoring Dawn. "Even without knowing what it looks like?"

"I don't know," said Giles. He closed the books, and began putting them back into the bag he'd brought over. "I believe some more research is in order. In the meantime, Buffy, I'd stay close to Riley. Make certain he doesn't do anything foolish, and try to discover if there is some other-worldly power influencing him."

"And… what about the two hostages tied up in our basement?" Dawn asked.

There was the sudden crash of a wooden board thudding against the floor. Buffy, Giles, and Dawn all snapped their heads around to the door leading to the basement. A pile of nails lay on the floor before the door, and the right side of the board had been completely unhooked from the wall.

"I think," said Buffy, as the entire board crashed to the floor, "they're not tied up anymore."

* * *

The Doctor produced the sonic screwdriver, seemingly out of thin air, and buzzed it against the ropes binding him. The ropes split apart, and in only a matter of seconds, the Doctor was free. He quickly freed Donna, then ran up to the top of the steps.

"Where are you going?" Donna demanded.

"Escape, Donna," he said, buzzing the sonic at the lock of the door. "No use staying down here. Universe to save and all that."

"By killing an innocent child?" Donna asked.

"She isn't real," said the Doctor. "Everything she is, everything she was, her entire life to this point — it's all just an illusion. A very complex and convincing illusion, but still just an illusion."

"You don't believe that," said Donna.

The Doctor paused in his work, for just a second. Then, he set his jaw, and buzzed the sonic against the door handle again. He pushed at the door, but it didn't budge. "Barricade? Deadlock seal?" muttered the Doctor, pushing again.

"Board nailed across the outside?" Donna proposed. She nodded over at the boarded-up windows surrounding them.

The Doctor looked around, examining the windows, carefully. "Wood." He shoved the sonic into his pocket, and ran a hand through his hair. "Ooh, she's good. Very, very good."

"Doctor!" Donna snapped at him. "What is going on?"

The Doctor looked down at her. "We're locked in a basement," he said. "While upstairs, Elizabeth is trying to work out—"

"Not that," said Donna. "With Dawn. You're never like this! You don't kill people."

"Dawn is not a person," said the Doctor, without any emotion in his voice. He sounded like he was trying to convince himself more than Donna.

"She bloomin' well is!" Donna snapped. "Look, what is she, exactly? You said she was some sort of segment."

The Doctor's eyes fell on a tool cabinet at the bottom of the stairs, and his face lit up. "Aha!" he cried, as he raced down towards it.

"Doctor!" Donna shouted.

"In a minute, Donna, I'm busy," said the Doctor, as he rifled through the cabinet.

Yeah, busy. Donna could see right through that one. Spaceman wasn't answering her because he didn't want to. Because he didn't want to think about what he was about to do, since — Donna was guessing — the more he thought about it, the harder it would be for him to do it. Well, good. Then Donna had to get him to think about it as much as possible.

Donna ran to the tool cabinet, and got as much in his face as she could. "Oi!" she said. "Just tell me what Dawn is!"

The Doctor glanced up at her. "Dangerous," he said.

"How?" Donna demanded. "How's she going to destroy the universe? What's this energy whatsit you keep going on about?"

"You don't need to know that," said the Doctor, as he returned to rifling through the tool cabinet.

"Says who?" Donna insisted.

"Says me."

The Doctor brought out a hammer and a bag of nails, then raced back up the stairs. He started knocking against the wooden door and the wall beside it, trying to detect the dimensions of the board and where it was attached to the wall.

"Well, I say I do!" Donna said. "Oi! Are you listening to me, Spaceman?"

But the answer to that was obviously no, as the Doctor fished the sonic out of his pocket, and buzzed it around the wall and door. He beamed.

"There we go!" he said, as he took out a nail, and started hammering it into the wall.

Donna knew she'd have to do better than that. She needed to find something that really got to the Doctor, something that would get past his denial.

"Doctor!" she said.

"Hmm?" asked the Doctor, continuing with whatever it was he was doing. A small tink sound rung through the air, and the Doctor switched his hammering to another spot.

"Just… think about this. About your friend?" Donna called. "Buffy. Elizabeth. Whatever you call her. She remembers Dawn."

"They're not real memories," said the Doctor, hammering. "They're implanted."

Tink!

"But that doesn't change how she feels!" Donna took a step forwards, up the stairs. "Doctor," she continued, in a quiet, gentle voice, "if you kill Dawn, you'll be killing your friend's sister."

The Doctor froze.

For a few moments, he didn't speak, didn't move, barely even breathed. Then he glanced back at Donna, his eyes burning with regret and pain. "I know," he said. With a slow, almost weary movement, the Doctor turned back, and resumed his hammering.

Donna couldn't speak. He knew. That Dawn was real, what her death would mean to Buffy, what that death would do to him. The Doctor knew exactly what he was doing, exactly what it meant. And he was going through with it, anyways.

A third soft tink of metal on the other side of the door. Like the drop of a nail. No, wait, it _was_ the drop of a nail. So that was what the Doctor was doing! He was nailing on his side of the wall, exactly where each of the nails was securing the board to the other side of the wall. As he hammered his own nail in deeper, he pushed the nail on the other side out of place, so that it dropped onto the floor.

Half the board crashed to the ground, and the Doctor quickly pushed in the final nail, so that the other half crashed down and the door flew open.

The Doctor rushed out of the basement.

Donna clambered up the steps towards the door, as fast as she could. She might not be able to talk Spaceman out of doing it. And she might not be a bloody Time Lord. But Donna Noble was going to save Dawn Summers, one way or another.

Because Donna knew that she was right.


	7. Chapter 7

Buffy prepared herself, as she watched the Doctor come out of the basement. She didn't have any weapons on her — didn't want any, to be honest — but she needed to make sure the Doctor didn't get out of the house. He wasn't killing Riley. She wouldn't let him. She'd find a way to get this Excalibur thing away from Riley herself, or…

Buffy didn't want to think about what she'd have to do if the Doctor was right.

Buffy crouched down, preparing herself for a fight. "Doctor," she said. "Stop, and listen to me. I can find out where this Excalibur is myself, I can make sure that no one has to die. I can do this another way."

"Oi, you listen to her, Spaceman!" Donna shouted, as she emerged from the basement.

The Doctor ignored Donna. He just met Buffy's eyes with his own. His eyes had always looked so sad, so terribly alone and so very soulful. Now, they were lined with something else. Something new. Something that Buffy hadn't seen before. A cold determination, a fixed intensity.

"I'm sorry," he said. "I am so, so sorry. You can't. There isn't any other way."

"Why?" Buffy asked. "What's happening? What are you so afraid of?"

The Doctor said nothing for a long moment, just looking at her. Staring at her. As if trying to come to terms with the implications of everything he was about to do. Then he blinked, and every emotion in his eyes faded back into that cold determination. "I'm sorry," he said, again. He broke away from her gaze, and turned to go.

Buffy jumped out at him, grabbing his trench coat and dragging him back from the door. He wriggled, and managed to extract himself from his coat.

She tried to knock him out again, but he dodged out of the way too quickly, this time, and she struck only air.

He ran towards the door, but she kicked out and caught him in the back, making him stumble and fall across the floor. She tried to catch him, but he rolled out of the way. Was he trying to make her hurt him? She was doing everything in her power not to actually cause him any physical harm — but considering her fighting techniques were all centered around causing physical harm, that was really difficult to do.

He started to get up, and Buffy charged at him, trying to pin him in place. He squirmed in her grip, twisting her own strength back against her, until Buffy, in a fit of rage, threw him over her shoulder so that he thunked, back down, onto the wood floor.

"Ow," he said.

"Stop fighting me!" Buffy shouted. "If you say that someone has to die to save the universe, I believe you. But _you_ shouldn't be the one to kill them!"

"I have to," said the Doctor, sitting up. "There isn't anyone else."

Buffy knelt down beside him. "There's me."

The Doctor's eyes widened, and his breath caught in his throat. Buffy thought she could see a flash of fear in his eyes, a flash of horror. "No."

"Just tell me what this thing is that we're looking for," said Buffy. "This Excalibur." She took his hands in her own. "Please. Explain it to me. What is it? What does it do? How can we stop it?"

The Doctor gripped her hands more tightly. "There is no we," he said. "Just me."

"I'm not letting you do this alone," said Buffy. "I know you're doing the right thing. I trust you. But you've got too much death on your conscience. Let me help you."

"No," the Doctor said. "You… no, just, no. Absolutely not."

"Why not?" asked Buffy. "Explain."

The Doctor said nothing.

"Doctor," said Buffy, very softly. "Please trust me. I want to help you. I know you don't really want to kill anyone; I know you're only doing it because you think it's the only way to save the universe. I understand that. But I also know you sometimes get upset enough that you overlook things. If you tell me what's going on, maybe we can work out a better way. Maybe we can find a way that no one has to die. Don't you want that?"

She could see in the Doctor's eyes that he did. Oh, he so wanted that. The cold determination dripped away from him, and Buffy thought, for a second, that she was getting through to him.

"It's…. I mean, the…. During the War…. It's more sort of…" the Doctor faltered. Then he sagged. "I can't tell you."

"Why not?" asked Buffy.

"Because if I tell you, you'll die," said the Doctor. "That's what always happens. Susan. Romana. Amy and Zara. Every person who's ever known about it was murdered, brutally murdered. Everyone except for me."

"Okay. Fine, then. How about I tell you?" said Buffy. "You're trying to find a key. Either because the key itself is dangerous, or you're scared the locked-up thing is going to get out. I'm guessing… this key's some artifact from the Time War, something that could tear the universe apart — or worse. You've worked out that someone I'm very, very close to has it, and you think the only way to get rid of this key is to kill… that person. Whoever it is." Buffy didn't want the Doctor to know she'd already worked out who it was. "You obviously don't actually want to kill anyone, and that's what's really freaking you out. You're worried about what'll happen if I stop you, and you're scared to death about what you'll do if I don't."

The Doctor almost stopped breathing at her words. The stony, terrible look settled back on his face, and his eyes reverted back to that cold determination. He yanked his hands away from her.

"Stop looking for answers," he commanded, trying to get to his feet again. "Stop trying to get yourself killed. And stop trusting me to do the right thing. Because I've rarely done anything nearly as wrong as what I'm about to do."

"Then don't do it!" Buffy shouted, grabbing his arms, and forcing him back onto the ground. "You're the Doctor. I'm the Slayer. I'm the one that kills stuff. You're the one that yells at me for killing stuff. So stop taking over my job!"

"I've killed before," said the Doctor. "For this thing. They wanted it, during the War, and I couldn't let them find it. I let two-thirds of this world die. I let families get wiped from time — not just killed, but never born in the first place. I let entire timelines get crushed. And I'd do it again — all of it, any of it — to make sure this thing doesn't fall into the wrong hands."

"That's not the same as killing people yourself," Buffy said.

"I killed Susan," said the Doctor. "Shot her right between the eyes, as she watched. I'll never forgive myself for that. But that's how much I've sacrificed for this thing."

"Who's Susan?" asked Buffy.

"My granddaughter."

Buffy's breath caught in her throat.

"Stop trusting me," the Doctor said. "Because this is worse than you could possibly imagine. Far, far worse. And there isn't any rule I wouldn't break to make sure it stays out of the wrong hands."

"But if Excalibur's a key, and everyone who knows about it is dead, then no one will ever use it!" Buffy said. "No one here has to die, Doctor! And even if someone does work out about Excalibur, I'm the Slayer. I'll be able to stop them."

"It's inherently unstable," the Doctor said. "Even a small energy fluctuation could create cracks in the Lock. It shouldn't even…" He trailed off, his face turning into a curious frown. "Wait a tic. Donna's been awfully quiet, recently."

Buffy stood up. "So has Dawn." She started racing around the house, looking for Dawn and Giles, but they were nowhere to be found.

The Doctor ran to the front door, and smacked his forehead with the palm of his hand. "Unlocked," he said. "Brilliant, Donna, bloody brilliant! The sun's about to set, the monsters are about to come out, perfect time to do a runner!"

"Let me guess," said Buffy. "You forgot to tell Donna that this particular town is right on top of a Hellmouth?"

The Doctor scratched the back of his neck. "It might have slipped my mind."

Buffy could work out exactly what had happened. Donna and Dawn had run off, probably to avoid the fighting. Dawn, always the little adventurer, wouldn't mind the danger, Donna wouldn't know about it, and Giles probably ran after them, shouting at them to stop.

The Doctor shrugged back on his trench coat (which Buffy hadn't seen him pick up), and began running out the door. Buffy chased after him. While Donna was in danger, the Doctor would be too worried about rescuing her to deal with any of the rest of it. That was Buffy's saving grace. But the moment Donna was out of danger, the Doctor would go back to trying to kill Riley. And Buffy wouldn't let the Doctor kill Riley.

They raced down the street, the Doctor flashing around his sonic, trying to detect something. He muttered something under his breath that didn't sound like English, then put the sonic away, licked his finger, and stuck it in the air. He made a face.

"It's no good!" he complained. "Too many psionics in the air. Can't get a good trace."

"I can," said Buffy. She pointed at where Giles had drawn a little x in the dirt of the front yard beside them. She could see another one in the distance. She ran forwards, and kept seeing more and more little x's. Thank you, Giles! She turned back.

And froze.

Because the Doctor was gone.

* * *

Giles and Donna were unconscious on the ground, on the sidewalk of a street some ways away. She shook Giles, and managed to get him up. Donna was still out.

"Buffy," said Giles, adjusting his glasses.

"Hey," said Buffy. "Little problem. The Doctor's off to kill Riley, and I still have to find Dawn. You wouldn't happen to know where Dawn is, right?"

Giles rubbed his head, and blinked, trying to get his wits about him. "There was… some sort of demon, as I recall," he said. "Yes, that's right. A demon. Tall, muscular, rather large wings. I believe it recognized Dawn and made off with her."

"And you just let it?" asked Buffy.

"I didn't have much say in the matter," said Giles. "I tried to get Dawn to safety, whilst Donna distracted the demon, but as you can see, I didn't get terribly far." He glanced over at Donna, and got to his feet. "We'd better make certain she's all right. She was rather… enthusiastic in her distraction."

"Don't tell me she tried to attack it," said Buffy.

"No," said Giles. "No. She seemed much more interested in… shouting at it. Quite loudly, in fact. I assume that's how you discovered us."

"I followed your x's," said Buffy.

Giles frowned. "Sorry, you followed my what?"

Buffy faltered. She was starting to get a very bad feeling about this. "You know, the little x's on the ground that told me where you were, and… you didn't make any little x's, did you?"

"No," Giles agreed.

Oh, yeah. That was bad. A demon that had specifically targeted her sister, and made sure that Buffy knew where to find Giles and Donna — the only two people who could tell her what had happened. That looked like some demon trying to give Buffy a sign or a message. The message probably being along the lines of: _I own this town, and you can't stop me._

This was all she needed, with the Doctor still out hunting for Riley. If the Doctor hadn't found Donna, yet, that meant… maybe he wasn't looking for Donna. Maybe he'd gone straight to Riley. Buffy shook Donna, but she wouldn't respond. Buffy checked her pulse. Still alive. Good.

"I believe she was hit rather harder than myself," said Giles. "The demon did seem quite annoyed by her."

Okay, okay. Buffy needed three people — one for Riley, one for Donna, and one for Dawn. And she had two — herself and Giles. Which meant… well, Buffy guessed that meant Riley was on his own, for now.

"Giles," said Buffy, "get Donna back to the house, and make sure she's okay. Then call Riley and tell him to find someplace safe and undetectable, and hide until I can get to him. In the meantime, I'm going after Dawn. Any idea where this demon thing took her?"

"No," Giles confessed.

Great. Even better. Wild goose chase. Buffy started to run, and hoped she'd find some sign to lead her to Dawn, before Dawn wound up in even more trouble.


	8. Chapter 8

It had come as a bit of a shock to the Doctor, when he realized he could see it. The energy. When he realized that he was far enough outside of reality that he could detect the segments to the Key to Time himself, without the use of a tracer. Born on a planet that never existed, in a time that had been folded away, in a part of the universe that had always been empty space… just remembering that, as he looked at Dawn, remembering that he was alone, so very alone…

It felt like losing Gallifrey all over again.

Except he wasn't. That was the problem. Because with Dawn around, the Key was unstable. The Lock could crack. Gallifrey could return.

The Doctor couldn't allow that.

But then Donna — brave, wonderful, brilliant, missing-the-bigger-picture Donna — had decided to take matters into her own hands, and get Dawn out of the house before the Doctor could do anything to her. The problem was, the Doctor hadn't been planning to do anything to Dawn inside the house. He'd been planning to disperse the energy that comprised Dawn's cellular structure from within his TARDIS. Now that Dawn was somewhere out in the open, the Doctor had to make sure that he found her, first, just to make sure the nasty that had gotten her hadn't picked up on what she really was.

And the Doctor knew a nasty had gotten her. He'd known the moment he saw those x's. Donna wouldn't have left Buffy a trail to follow — she didn't want the Doctor to follow them. If Giles had been the one to leave those little marks, he would never have kept up with Donna and Dawn, who were probably running. Which left only one other option — some nasty had been trying to lead Buffy away, so he could kidnap Dawn.

Which was only confirmed by the fact that the Doctor could vaguely sense the time energy that was Dawn Summers coming from a different direction than the x's.

So the Doctor ran off, following his own instincts and the very slight tingling sense in his head that he knew meant Dawn was around. It was difficult, but he was quite clever, and he shortly found himself at the mouth of a very large and normally very dark cave.

With a series of lit candles lining the passage inside.

The Doctor crept forward, down the cave, moving as silently as he could. A part of his brain kept screaming at him to think about what he was going to do when he found Dawn, screaming at him that he couldn't possibly go through with it. Most of the rest of his brain was occupied with blocking out the screaming part. He couldn't help but realize, with a spark of hope so disgusting it reviled him, that perhaps this demon would finish the job for him.

He hated himself for thinking that.

He could hear voices, from some ways ahead of him, down the twisting passageway. He paused, though, as he noticed the Trifaldoreign interspatial warp control box lying nearby on the ground. Most people probably wouldn't know what it was. In fact, it looked rather like a great big hunk of rock. The Doctor knew better.

Trifaldoreigns. Ah, yes, that made sense. The Doctor knew the Trifaldoreigns. Big bossy interdimensional sort, with horns and teeth and wings and the works. The sort that Buffy would probably call 'Random Demon-Looking-Thing Number One', if she were here (don't think about her, she's going to despise you after this is over). Except they usually were less keen on the random acts of brutality and more keen on massive planetary invasion. Specifically the primitive planets that hadn't made interstellar contact, yet, and particularly the ones with sentient creatures the Trifaldoreigns could feed on.

The Doctor tried to drag up the bits of his memory about Trifaldoreigns. Ah, that was right — they didn't come all at once, did they? They didn't have enough power to create a huge portal without using an interspatial warp conduit on both sides. The scout would go first, identify the individuals that the Trifaldoreigns would consider the biggest threat — their future enemies — then annihilate their enemies' family members and leave their corpses to be discovered. The discovery of these corpses would lure the enemies to the warp conduit. The moment the enemies arrived, the Trifaldoreign scout would activate the warp conduit, and the entire Trifaldoreign army would march in and stomp their enemies out.

Seems Buffy had been identified as enemy number one.

The Doctor easily took apart the control box for the warp conduit, pocketing a few essential pieces so that there would be no way the army could get to Earth. Well, that was the invasion taken care of, then. One Trifaldoreign left, but the Doctor could take care of him later.

After the Trifaldoreign had finished its first objective.

The Doctor continued down the cave, sneaking through the twisting passageways, until he could hear the voices coming through far more clearly. He pressed himself against the wall of the cave, lurking in the shadows. Edging forwards, the Doctor peered around a curve in the passageway. There, he could see Dawn, chained to the wall, the temporal energy rippling around her in a steady green glow. The Trifaldoreign scout was pacing the room with great, lumbering footsteps, his claws glinting in the candlelight. He'd chained up Dawn, set up a way for Buffy to discover what had happened. Which meant the next step was coming soon. The Trifaldoreign was going to kill Dawn.

And the Doctor was going to let him.

(He hated himself so much sometimes.)

The Trifaldoreign scout paced the room in front of Dawn, examining her carefully, clinically. Trying to use her to identify weaknesses in the human race, the Doctor assumed. The Trifaldoreign would probably tear Dawn's body apart, trying to examine all the inner workings and figure out what made humans tick.

(She isn't real. She's just energy. All her memories are false, implanted. None of the things she remembers ever really happened—

None of the things he remembers really happened, either—

No! That doesn't matter. Susan was a real person. She died for the Key. Romana was a real person. She died for the Key. All those children Rassilon had butchered were real, too, and they had died for the Key. What was one more? What was one more?)

It hurt too much to think about.

"You better let me go," Dawn shouted at the Trifaldoreign scout. "Because I've got an older sister who's going to kick your butt."

"The Slayer," said the Trifaldoreign. "I know. Your corpse will be a fine gift to her from my people."

"Yeah? Well, you say that now, but Buffy's going to come save me!" Dawn snapped. "She always does."

"No one's coming," said the Trifaldoreign. "No one even knows where you are." The Trifaldoreign drew up a long sword from the scabbard along his belt, and put its edge against Dawn's throat. "Your little Slayer isn't going to rescue you this time."

Your Little Slayer.

Those words.

Racing through the Doctor's body like an electric shock, burning inside of him like the ash from a hundred thousand volcanoes all at once. Your Little Slayer. Searing through his mind. Your Little Slayer. Tearing at his hearts.

_you killed them all Doctor you killed them you watched them die and you didn't even care you didn't save a single one..._

Another Elizabeth. Another timeline. He remembered. Her blazing blue eyes, the way her blond hair tumbled across her cheek as she glared at him, the hatred etched into every feature of her face.

(He'd destroyed her, once.)

_evil heartless soulless inhuman tearing me apart from the inside out just Your Little Slayer that's all I ever was to you just Your Little Slayer that you could use and then destroy_

(He had destroyed her, so long ago.)

The pain and anger and desperation in her voice, the way every word struck at him, harder than any physical blow.

(Could he do it, now?)

_hate you hate you wish I'd never met you Doctor wish you were never born!_

(Could he do it again?)

The Doctor didn't realize he was moving. He didn't realize he was speaking. But the next thing he knew, he'd strolled up to the Trifaldoreign scout, hands in his pockets, an easy smile on his face.

"Well," he said, "hardly fair to expect her to solve all your problems. Busy girl and all that. Thought I'd give her the night off."

The Trifaldoreign hissed, and in one swift movement, he removed the sword from Dawn's neck to point at the Doctor.

"Oi, watch it," said the Doctor, raising his hands in the air. "You'll poke someone's eye out with that."

"Who are you?" the Trifaldoreign demanded.

"I'm the Doctor," said the Doctor. "Hello!"

"Are you the ruler of this world?" asked the Trifaldoreign, inching the sword closer.

"Well, not exactly," said the Doctor. "In fact, not at all. Although, I am rather attached to it. Better to call me… Earth's champion. That has a bit of a nice ring to it, don't you think?" He winked at Dawn.

"Your name, puny human," the Trifaldoreign demanded. "Speak, or I shall skewer you where you stand. I have an army waiting to invade this world, and nothing you can do will stop me!"

"Ah, actually, no name, and not human," the Doctor said. "And as for the army, well, they're not coming. Might have had a rummage around in your interspatial warp controls earlier. A bit sloppy of you to leave them lying around in the open."

The Trifaldoreign roared, clearly preparing to run the Doctor through with his sword, but the Doctor activated the sonic, making the Trifaldoreign fall back as the piercing sound rang through his head. The Doctor darted out of the way, and unlocked Dawn from the chains.

"Where's Buffy?" Dawn asked him.

"Not a clue," said the Doctor. "Looking for you, at a guess." He glanced over, noticing that the Trifaldoreign had now gotten to his feet, and was looking at the Doctor as if baying for his blood. "Probably shouldn't stick around here to wait for her, though. Allons-y!" And the Doctor grabbed Dawn's hand, and ran towards the entrance of the cave.

The flap of wings echoed through the cave, and Dawn gave a little cry, grabbing his hand even tighter, as she abruptly stopped running. The Doctor looked back, and noticed that the Trifaldoreign had grabbed Dawn's shoulder with its claws, and was trying to pull her back. The Doctor's eyes flicked across the top of the cave, and noticed the rock formations directly above where the Trifaldoreign was flying. The fissures that lined the rock's surface. Town built on both a fault line and a Hellmouth — bound to be instabilities built into a cave like this.

"Ready to run faster than you've ever run in your life?" the Doctor asked Dawn.

Dawn just squeaked, as the claw curled into her shoulder a little tighter.

The Doctor activated the sonic, pointing it at the top of the cave. Things began to tumble down from the roof of the cave, dust and debris and big chunks of rock. The candles flickered out, and as he felt the Trifaldoreign let her go, the Doctor yanked Dawn down the passage towards the mouth of the cave, up ahead. The Doctor pulled her out of the cave just as the entrance sealed shut behind them.

They stood, for a moment, in the woods right outside of Sunnydale, in front of the sealed cave, catching their breaths. It was only then, when the cool night air stung the Doctor's face and the adrenaline wore off, that the Doctor realized what had just happened. And what hadn't.

"What have I done?" he asked himself, staring at the sealed-up cave entrance.

"You saved my life," said Dawn.

He turned to her, that girl that rippled with glowing green energy, that girl that sang with the song of the Vortex. The most dangerous girl in the entire world — no, the entire universe.

"I saved your life," the Doctor repeated.

"Yeah," said Dawn. She tucked her hair behind her ears. "I mean, um, thanks. Just, you know. For the rescue and stuff." She said nothing for a few minutes, just watching him, carefully. "I think I get why Buffy likes you so much."

The Doctor gave Dawn a grin, and extended a hand towards her. Dawn took it. And in that moment, when their hands met, when the Doctor looked into her blue eyes — blue, just like her sister's — and could see that same trust and hope and compassion that he saw, so often, in Buffy (the look he'd seen and lost, so long ago, from Elizabeth) — that was when the Doctor knew.

He couldn't.


	9. Chapter 9

When Donna came to, she found herself back at Buffy's house, lying on the couch, an excited teenage voice buzzing in the air around her.

"And then the Doctor was all like, 'yeah, well you left your crazy spacey sounding control stuff out in the open, where I could break it, what do you think about that?' And the demon was like, 'Aaaaa! I'm going to kill you!' And the Doctor was like, 'You can't kill me, I've got the Annoyinator'—"

"Sonic screwdriver," Buffy cut in.

"Whatever," said Dawn. "And then the Doctor took the chains off, and we started running, and he was all like, 'you better run faster than you've ever run in your life,' and then the entire cave started crashing down on top of my head, and—"

"Donna?" came the Doctor's voice. Donna's eyes panned across the room, and landed on the Doctor. He seemed completely at ease, with none of that previous darkness in his eyes. Or maybe that was him trying to act all normal and reassuring again. No, hang on. What Dawn had just said…

"Did you save her life?" Donna asked the Doctor.

The Doctor grinned at Donna, and winked.

Donna collapsed back onto the couch. She'd done it. She'd guilted him into being unable to kill Dawn. Victory Donna Noble! Score! Except… if the entire universe came to an end. Then she'd be slightly less happy.

"Well, now that Donna's awake, I suppose we should be off," said the Doctor to Buffy.

"I thought you were looking for Excalibur," said Buffy. "Aren't you going to stay until you find it?"

The Doctor gave a small shrug. "Nah. Excalibur's overrated. Not all that important, anyways."

"You know, if you're going to lie, you could at least do it convincingly," said Buffy. "Come on. What's the real deal?" She studied him, carefully. And then her posture relaxed, as she worked it out. What Donna had worked out. That the Doctor had decided he couldn't do it. Buffy gave him a smile, then flung her arms around him. "Thank you."

And that was definitely not a just-mates hug. On either side.

Looked like Skinny was finally getting over his Rose fixation. Bout time, too. Donna didn't know exactly how long it'd been for him since he lost Rose, but it had obviously been way too long to keep moping about it.

Dawn caught Donna's eye, and made a kissy gesture with her fingers. Donna laughed. The Doctor pulled out of the hug, and Dawn shoved her hands behind her back, trying to look innocent.

"Something the matter?" he asked them.

"No," said Dawn. "Nothing."

The Doctor raised an eyebrow. Then he turned back to Buffy, and spoke in a low voice. "Don't investigate this, don't pry any further than you have to, don't try to find Excalibur. Keep your eye on everyone you know, make sure no one suspicious is following you or tracking your actions. And for the sakes of everyone you know and love, don't tell another soul about anything that happened today."

"But if Excalibur is still dangerous—"

"I'll be back," said the Doctor. "I promise. Donna and I will be back, just to make sure everything's fine and dandy." He glanced up at Donna. "Won't we, Donna?"

"Long as you let me treat Dawn to a shopping spree courtesy of your psychic paper," said Donna.

The Doctor gave a small sigh, then flicked his eyes back to Buffy. They stayed that way, a little too close together, a little too touchy feely, a little too… well, a little too not-just-matesy. Then, without having to say anything, they broke apart. The Doctor hopped over to Donna, and offered her a hand up off the sofa. "Come along, Donna," he said. "Time and space await."

* * *

Buffy escorted them back to the TARDIS, just to make sure that the Doctor didn't do anything. The Doctor didn't mind. The moment the Doctor and Donna entered the TARDIS, the Doctor began his dance around the central console, as he programmed in their next flight. Donna closed the doors, then sat on the jumpseat, watching him.

"You couldn't do it, could you?" she asked. "I knew you couldn't."

The Doctor gave Donna a long, dark stare, then went back to his work at the central console. It was a stare that reminded Donna that this alien she was travelling with had done things she couldn't even imagine, things that she probably didn't want to know about.

Was that whole thing back at the house just an act?

"You're not going to kill her, right?" asked Donna. She was starting to wonder if she needed to shout at him a bit more, or if she should go all out with the slap offensive.

"I'm not," the Doctor agreed. He sighed, and slumped over the central console. "I can't," he confessed. "Not ever. It's the one thing I could never, ever bring myself to do." He stared at the buttons beneath him, a terrible look of defeat on his face. When he next spoke, his words were little more than a whisper. "I can't destroy her. Not again."

"Who?" asked Donna. "Dawn?"

The Doctor said nothing for a long moment. A moment that stretched into a vast chasm of time that seemed to roar with memories the Doctor couldn't forget, with pain and loss and the weight of two different timelines stretching across the universe.

"Yes," he said, at last.

And Donna knew he was lying.

* * *

The End


End file.
